My guess will be you have the TV connected in to the wrong scart, as the volume control only has an effect on one of them. Having said that I don?t think you would get the bar running up and down as it also only gives graphics over one scart. But I would have a look anyway.

In case anyone's interested, this is indeed the solution for this weird problem.

On my 5800 located in a cabinet, the rear SCART cable fell off and I blindly hooked it back up by feel. I must have inadvertently put it in the wrong (VCR) socket because the volume control no longer worked with the remote.

The other issue was the TV no longer auto switched over to the SCART input when the Toppy was switched on from off so it appears the VCR connection was obviously not geared to sending a sync signal the other way.

Apologies for the bump but I found this thread via the search facility and hope it helps someone else.